Direct injection diesel engine

Abstract

A direct injection diesel engine includes a cylinder head which is formed, for each cylinder, with a plurality of intake ports. At least one of the intake ports has an approximately straight throat extending tangentially to the cylinder and opening into a combustion chamber at upper reaches of swirling. Another of the intake ports has a throat opening into the combustion chamber at lower reaches of swirling. A glow plug extends downward from one side of the cylinder head, at which the intake ports open, toward a location between the other intake port. An exhaust port extends from another side of the cylinder head and opens into the combustion chamber.

What is claimed is: 
     
       1. In a direct injection type of diesel engine having a cylinder head which is formed, for each cylinder, with a plurality of intake ports, extending downward from one side of the cylinder head and opening into a combustion chamber on one side of a transverse center line of the cylinder spatially intersecting perpendicularly a center line of rotation of a crankshaft, and at least one exhaust port, extending from another side of the cylinder head and opening into the combustion chamber on another side of the transverse center line, and which is provided, for each cylinder, with a glow plug directed toward a concavity of a piston head, the improvement comprising: at least one of said intake ports having an approximately straight throat which extends, in a plane perpendicular to a vertical center line of the cylinder, parallel to a tangent to the cylinder and opens into said combustion chamber at upper reaches of swirling produced in said combustion chamber;   another one of said intake ports having a throat which opens into said combustion chamber at lower reaches of said swirling; and   said glow plug extends downward from said one side of said cylinder head toward a location between said other one of said intake ports and said at least one exhaust port.   
     
     
       2. An improvement as defined in claim 1, wherein one end of said other one of said intake ports, at which said other one of said intake ports opens into said combustion chamber, is located in closer proximity to said transverse center line than one end of said at least one of said intake ports at which said at least one of said intake ports opens into said combustion chamber. 
     
     
       3. An improvement as defined in claim 2, wherein said glow plug extends so that an extension line of said glow plug intersects said transverse center line at a certain angle. 
     
     
       4. An improvement as defined in claim 2, wherein said glow plug extends below and overlaps at least partly with said other one of said intake ports. 
     
     
       5. An improvement as defined in claim 2, wherein another end of said other one of said intake ports is located higher, in vertical position, than another end of said at least one of said intake ports. 
     
     
       6. An improvement as defined in claim 5, wherein one end of said glow plug, at said one side of said cylinder head, is located higher in position than said other end of said at least one of said intake ports. 
     
     
       7. An improvement as defined in claim 2, wherein said throat of said other one of said intake ports is approximately straight and extends in a plane perpendicular to said vertical center line of the cylinder and parallel to a tangent to the cylinder. 
     
     
       8. An improvement as defined in claim 7, wherein another end of said other one of said intake ports is located higher, in vertical position, than another end of said at least one of said intake ports and has an ejection angle at which air is ejected into said combustion chamber which is larger than that of said at least one of said intake ports. 
     
     
       9. An improvement as defined in claim 8, wherein said glow plug extends below and overlaps at least partly with said other one of said intake ports. 
     
     
       10. In a direct injection type of diesel engine having a cylinder head which is formed, for one cylinder, with a plurality of intake ports opening into a combustion chamber and at least one exhaust port opening into the combustion chamber, and which is provided, for one cylinder, with a glow plug, the improvement comprising: at least one of said intake ports being positioned on an upstream side of at least one other of said intake ports and with respect to a direction of air swirl in the combustion chamber and formed as a tangential type intake port so as to introduce air into the combustion chamber in a direction parallel with a tangent to the cylinder; and   said glow plug being disposed such that one end of said glow plug projects in the combustion chamber and is positioned between one end of the tangential type intake port opening into the combustion chamber and one end of said exhaust port opening into said combustion chamber.   
     
     
       11. In a direct injection type of diesel engine as defined in claim 10, the improvement further comprising the cylinder head being formed, for one cylinder, with two intake ports, each of said intake ports being positioned on an upstream side with respect to a direction of air swirl in the combustion chamber and being formed as a tangential type of intake port so as to introduce air into the combustion chamber in a direction parallel with a tangent to the cylinder. 
     
     
       12. In a direct injection type of diesel engine as defined in claim 10, the improvement further comprising said glow plug extending below and overlapping partly with said tangential type intake port as viewed from above the diesel engine. 
     
     
       13. In a direct injection type of diesel engine as defined in claim 10, the improvement further comprising said at least one of said intake ports and said exhaust port being positioned on opposite sides of a transverse center line of the cylinder, respectively. 
     
     
       14. In a direct injection type of diesel engine having a cylinder head which is formed, for one cylinder, with a plurality of intake ports and at least one exhaust port opening into a combustion chamber, and which is provided, for one cylinder, with a glow plug, the improvement comprising: said intake ports having first ends which open at a same level at one side of the cylinder and extending downward from said one side of the cylinder and opening into the combustion chamber;   at least one of said intake ports, which has a tangential throat, and said exhaust port being positioned on opposite sides of a transverse center line of the cylinder; and   said glow plug extending from between top and side walls of the cylinder head toward a location between said at least one of said intake ports and said exhaust port.   
     
     
       15. In a direct injection type of diesel engine as defined in claim 14, the improvement further comprising said glow plug extending below and overlapping partly with said at least one of said intake ports as viewed from above the diesel engine.